Twin-bar suspension-insulator



S. S. SONNEBOHN.

TWIN BAR SUSPENSION INSULATOE.

APPLICATION FILED JuLYio. 191e.

Patented Apr. 20, 1920.

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SOL S. SONEBORN, 0F BROOKLYN, NEW YORK.

TWIN-BAR SUSPENSION-INSULATOR.

Specification of Letters Patent.

Patented Apr. 20, 1920.

Application filed July 10, 1918. Serial No. 244,140.

To all Iwhom it may concern Be it known that I. SoL S. SoNNEBoRN, a citizen of the United States, and a resident of Brooklyn, county of Kings, and State of New York, have invented certain new and useful Improvements in Twin-Bar Suspension-Insulators, set vforth in the following specification.

This invention relates to strain insulators. Its object is to produce a strain insulator less subject to breakdown than any heretofore produced.

In carrying out this general object I propose to combine with a pair of separated terminals two or more connect-ing stripsof insulating material, each or all of which are protected against the weather by a covering of molded insulating material.

Many further detailed objects of the invention are apparent from my specification.

The above will better be understood by reference to the illustrative embodiments described in detail in the following specification, which has reference to the accompanying drawings forming a part hereof,`in which like characters designate corresponding arts. In the drawings- Figure 1 is a vertical elevation, wuth parts shown in section, showing a series of my insulators in accordance with my invention;

Fig. 2 a horizontal section. with parts shown in plan, of one of my single insulator units; and v Fig. 3 is a vertical section correspondiingl in size to Fig. 2,-showing one of my insulator units, parts of which are shown in elevation and parts broken away.

Heretofore many insulators have been broken down needlessly because they have 'been subjected to strains far above what they could stand. Electrical engineers without diti'iculty can figure what an insulatoi' unit or a series of insulator units can withstand. but up to the present date no one has definitely prescribed the detailed specifications within which a string of high tension insulators should be safely einployed.

It is a main object of my invention to provide a string of insulators including specially designed units, which may be em- -ployed with impunity, regardless of the potential diderence placed upon the saine by their users. a

More particularlyv it is an object of my invention to provide a series of strain insulators of the type which support a conductor calculated to carry a potential of relatively great difference. between it and ground. For this general objectit is further an objective feature of my invention to provide an insulator unit which may be employed in `series with a plurality of the same insulator units or with others.

Paying particular attention to one feature of my invention, an object is to provide in combination with an insulator a sparkgap. the breakdown values of which are less than the ultimate breakdown between the terminals of the insulator with which it is associated.

Referring more particularly to the specific embodiment of my invention, an insulator unit is indicated by A. This unit comprises two or more parallel spaced tension strips 1. In the embodiment there is illustrated a single pair of strips. Preferably these strips are formed of hydraulically compressed fiber or such material as is known in the art as micarta. lTo reduce the tendency for surface leakage on account of the stratified character of this structure. the edges are interrupted by indentations 3, If desired the interruptions of the continuity of the strata or fibrous continuity of these strips may be effected by transverse perforations as illustrated and described in my copending application` 757A, office docket.

Fundamentally` this application is applicable to an embodiment in which ay pair or several connecting links of insulating inaterial l are connected mechanically with separated terminals l and 5 by means of suitable cross-pins such as the crbss bolt o, which centrally penetrates the eye 7 of thc terminal S.

It is preferred that an insulating bushing` 9, which may be either of integral construction. as shown, or of concentric tubular construction, as desired, serves as the mechanical connecting means between the pin 6 and the links l.

In the construction of each link, eacb terminal 8, which is preferably formed of conducting material such as malleable iron, has an eye 10, the interior of which is faced with an insulating bushing 1l of conducting niaterial, which itself is preferably reinforced by a lining 12 of abrasive resisting material such as copper, brass or plated sheet iron.

The insulated structure previously described is preferably inclosed in a casing B of molded insulating material, which envelops the tension strips l and the terminals l0.

In many cases an insulator is subjected to electrostatic'strain beyond its calculated limit. In this construction each terminal is provided with an electrical extension :20, which serve as connections for the horn gaps C, which are preferably located vertically above the air space 2l intermediate the connecting links l, so that in the event of an arc, the upward current ot' air through the space 2l directly across a gap C is serviceable in blowing out the arc. v

Adjacent spark gaps C are preferably connected with conducting clips 22, attached to posts 20. These clips are'obviously vertical in parallel to the flexible link connections 23, mechanically uniting two contiguous insulator units so that no electrical strain can'exist between the eye of one insulator unit andthe mechanically coupled eye or" the next unit. This feature is beneficial in preventing puncturing through the insulators of the series.

The ground end of a string ot my insulator units such as the string I) of Fig. l is shown connected in an obvious manner with a suitable support 2l, through the medium of one ot my connectors Q3. It is preferred that the end Q5 ot the horn C adjacent ground be down into substantially electrical connection with ground, as indicated.

It should be noted that the horn gaps C are adjustable in the posts 2O through any suitable means such as the set-screw 26.

That I claim and what I desire to secure by United States Letters Patent is 1. In a system of strain insulator suspension. a ground; a string of one or more insulator units connected with said ground; each insulator unit comprising separated terminals and an insulating connecting link; and r unded one or more series spark gaps, one or each said link.

2. A strain insulator comprising a pair of separated terminals of conducting material; a connecting link of insulating inaterial for said terminals; and a spark gap bridging said link and connected at its ends with said terminals. I

3. A strain insulator comprising a plurality of parallel tension strips of insulating material; a pair of separated terminals; and means insulated from said terminals for connecting said strips to said terminals.

4. A strain insulator comprising a separated pair of parallel strips of insulating material; a pair ot separated terminals; and insulated means connecting said strips and said terminals.

5. An insulator comprising two separated .metallic terminals; an insulating link means connecting said terminals and providing a vertical opening; and a spark gap connected with said terminals and located directly above said opening.

G. A. high potential insulator comprising two conducting terminals and a body of insulating material having an opening forming a duct for the passage of air; and sparkgap elements connected with said terminals and' located so that said spark gap is subject to the tlow of air through said duct.

7.'A series ot strain insulators mechanically connected between a support and a conductor and inherently constituting Zones of greater vand less insulating value; and a circuit including spark gaps paralleling said series with one spark-gap opposite each said insulating portion of greater value and terminally connected between said support and osaid conductor.

8. A series of strain insulators for line support, each comprising separated insulating links adapted to lie in a horizontal position so that an upward flow of air is permitted between said links; and a series of spark-gaps one for each insulator connected in parallel with said insulators so that each said spark-gap protects an insulator of the series.

In testimony whereof I have signed my name to this specification, this 14th day of Mayl918.

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